I don't think that's correct. It applies only to early FS98 gauges. Most of the FS9 GAU files I've tried work in FSX. Sound files appear to work fine but should be kept in their respective Sound folders. IMHO
The best way round this is to paste 3rd party gauges into the Panel folders of the aircraft they belong to. If you paste them into FSX\Gauges be very careful not to overwrite existing gauges or use gauges in different formats with the same file prefxes.
I believe what your saying Hagar, though when FS9 gauges load in FSX, there are all sort of error messages which appear and ask whether you want to load those file's or not. Some are and some aren't, that's why I stated that they might not work 100%. The FS9 sound files, I found not to work, because while loading it in the default aircraft directory, there wouldn't be any sound that could be heard.
